Vibrator



`lune 25,' 1946. v H BENlol-F 2,402,593

VIBRATOR Filed March 51, 1944 2 sheets-sheet 1 IN VEN TOR.

HUGO BENIOFF fan VIP2o 2 Sheets-Sheet 2 llllli il III VIBRATOR H. BENIOFF Filed March 5l, 1944 June 25,V 1946.

INVENTOR.

\ l HUGO BENIOFF retenue .time 25, ieee ,siste WHBEEATR v Hugo Bendorf?, "Fasaderia, Calif., assigner to Sub marine Signal Company', Boston, Mass., a cor-3 poration ci Maine Application March Si, ibid. Serial No. 529,@li

(Ci. TX2-it) The present invention relates to a vibrator designed to produce mechanical vibrations for con trolling electrical circuits to produce alternating or pulsating currents. The aim ci' the device ci the present invention is to provide reliable vibratepositioned at the center of the ribbon which is a quasi node for both vibrating sections. The fixed contact screws limit the ribbon amplitude at this point to small velues and thus establish a quasi or approximate node.

This and other features of the present invention will be more thoroughly understood when considered in connection with the drawings illustrating an embodiment oi `the same in which Fig. l shows the invention in elevation with parts shown in fragmentary section; Figjz shows a top plan View of the invention looking down upon' the View oi'Fig. l; Fig. 3 shows a bottom plan view of the invention looking up from the loottom of Fig. l; Fig. 4 shows; a section taken sub stantially uponfthe line l--ii ci" Fig. i; Fig. 5 shows a section taken substantially upon the line of Fig. 1; Figi 6 shows an end viewas viewed from the right end of Fig. l; Fig. TI shows a circuit diagram showing the control circuit for operating the vibrator and also the control of the electrical circuit obtained through the motion of the vibratory ribbon; Fig. 8 shows a section taken on the line 8-8 of Fig. 1 and Fig. 9 shows a mode of vibration which the vibrator may undergo.

In the vdrawings the device comprises a heavy base member l which is elongated and serves as a spanning support over which a ribbon 2 is placed and held taut at both ends of the base by clamping members or plates Sv and 1. The

clamping plate 1 clamps directly to an upwardly extending end portion 4 of the base `while the clamping plate 6 clamps to an adjustable support 3 which maybe adjusted in a longitudinal direction with reference to the ribbon so as to obtain the desired tension. For this purpose the end support 3 is provided with a topclamping block 8 and two recess channels 9 and Ill in its side faces, which recessl channels receive forked extensions Il and I2, of 'the base l. A machine stud or bolt I3 passes throughthese forked ends Il4 and I2 and through an elongated slot i2' elongated in the direction ci the ribbon and iongitudinally with the base in the stern portion oi the block:

An adjustment screw ifi passes through the bloclr ci 'the support S from .the end working against the end ci the base i. in adjusting for the desired tension on the ribbon 2 this adjust'u ment screw M is turned yuntil the desired tension is obtained on the ribbonand the nut it may tightened clamping the bloc-li rigidly in place. The frequency oi the vibrator may be adjusted in vthis way. v

The ribbon? is vibrated electromagneticaliy by means ci two spaced armatures it and it?. These armatures comprise a top clamping plate or bloeit il and a lower member' it. These two members W and iii are positioned one on either side oi the ribbon and arelclamped to the ribbon and to each other through the clamping screws it. The low er block l@ is recessed to receive a stack o arman ture laminations 2d which are held within the ren cess of the holder it by means oi a pair oi `screv-Js it which pass through holes in the side o the holder iii. The outer corner faces oi the lamhia1 tions E@ come normally in proximity to the pole members 2i and 23. These are poles of the electromagnet 26, which is made up of a stack o Ue shaped laminations 25 which have energizing coils i@ and El placed upon each oi the pole eiem ments. This structure is duplicated in,v both' halves of the apparatus. The laminatiohs Zit' are held in place by means of a clamping plate 2@ which is held to the side of the base i by the screws 2d. The electromagnet with its exciting coils are set in a recess in the base l, which recess is made to receive snugly the laminations and permit the coils` to iit over the pole arms. The structure is further held in place by means of clamping brackets 29 and 30 which are provided with shoulders extending over the upper outer corners oi the laminations. The brackets 29 are clamped to the base I by means of screws 3l while the brackets 30 are joined together by a central element 32 which is bolted to the base by means of screws 33 and 34. The electromagnet structure, therefore, is rigidly assembled in the base but may be removed for changing of the coils or for any other purpose. f

The arma-ture laminations attached to the ribbon are not limited in their transverse motion since the armature lamina/tions clear the poles 22 and 23 and dip between them in the vibratory motion of the ribbon. I

The manner in which contacts between the ribbon contact points and the stationary Contact other holder or support 6|.

Y 3 screws resulting from vibration of theribbon operate, will now be described. These contacts are positioned substantially halfway between the clamping ends 6 and 1 and are likewise substan` tially the same distance from the two armatures on the ribbon.

Attached to the Vbase I midway between the ends are two side brackets Il and Il4 which are held to the base through side screws I! and Il. respectively. These brackets Il and 4I have shoulders formed from the inner side of the bracket outward recessed into the bracket as indicated at M. Positioned in this recessed shoulder on one side is the contact holder or support Il which is held to the bracket by means of a screw Il passing through the wall of the bracket and entering into the end of the holder 8l. The holder 8l is tapped to receive the contact screw l2 which may be adjusted vertically, as indicated in Fig. 4, with reference to the ribbon 2 on which the opposing contact points I! and il on one side and 51 and B8 onthe other side are rigidly fixed by welding, soldering or any other desired means. VThe contact screw 52 is adjustable up and down for the desired position and for this purpose the member 32 is recessed to-prevent electrical contact therewith'if desired. As indicated in Fig. 4 the contact screw 52 is not insulated from the supporting bracket Il although this may be done if desired, as is the case of the This is Sumorted by means of the screw 41 and the member Il rests in a shield 45 which separates the holder 6| from 4the bracket 4I. The contact screw 58 is adjustable in the holder Il. When proper ad- Justinent has been obtained, the clamping screws '53 is completing the circuit of the contact B1 on vthe ribbon while the other stud contactsI l2 and 54 are positioned to the rlbboncontacts Il and lt. Contacts 51 and 53 open and close4 the circuit to the electromagnets whereby periodic traction on the two ribbon armatures is effected. The contacts 52 and work with'the contacts Il and bl to supply energy to the load 14. 'Ihis double contact system for the load 14 provides that contact frequency is supplied at double the vibration frequency of the ribbon.

Fig. 9 illustrates the mode oi' vibration oi the ribbon where both sets of electromagnets are simultaneously energized in a mannen in accordance with the circuit of Fig. 7. This motion is a forced vibration in which a quasi node exists' at the midpoint of the ribbon. Since each l2 'and 83 may be tightened for tightening the split tap in which the contact studs I2' and 58 thread. While this construction is not shown in the drawings, it is the same as the construction for the holders of the top contact members Il and Il which are supported in the. holders 4l and I! clamped by means of screws l. and BI to the top surface of the brackets Il and 4i. 'I'hese holders 4U and 9, as indicated in Fig. 2, are tapped to receive the contact stud screws 5I and B5. The holders I8 and Il are slottedas indicated at 84 and the slots extending from the tapped holes for the studs Il and Il to small recesses or holes in the pieces 4l and 4l in the same direction as the taps. The screws l1 and entering themembers. and, respectively. from the sides tighten the studs in the taps after these have been set in proper positions. The contacts 56 and Il and I1 and l! are shaped to have a bevelled or knife edge running transverse to the longitudinal direction of the ribbon, thus fixing the length of the ribbon from the clamping point to the point of vibrational contact.

The electrical energizing system which may be employed is indicated in Fig. '1 Cl e. .1 to elements in Fig. 1 the circuit of Fig. 'I comprises four coils 2l, 20, 21, 21 across which a 1 condenser 10 may be placed for timing or par- M tially tuning the electrical circuit tothe frequencies.of the mechanical vibrationsoi' the ribbon.

The condenser and coils may be attimed toa harmonic or a multiple of a half harmonic such that the contacts of the vibrator will open at instants when the current across the contacts is substantially zero( That is to say. the oscillations oi' the condenser circuit should be such that the current across the contacts is nero at the instant that the contacts are opened. This, of course, refers to the steady-state condition set of electromagnets simultaneously pulls the armatures on the ribbons in synchronous motion, a vibration is built up with .the maximum amplitude occurring at the place of the armatures and the minimum amplitude with the greatest transverse force occurring at the point oi contact. The ribbon frequency is determined by the mechanical constants of the ribbon Such. for instance, as its length, its tension and the manner in which it is Weighted. For general purpose the string or ribbon vibrator may be called a loaded duplex" ribbon vibrator.

'I'he contacts 56 and 58, Fig. 9, while moving with only a smallamplitude, nevertheless move with considerable force and therefore provide reliable and positive contacts at the points.

Having now described my invention, I claim:

1. A vibrator oi' the type described comprising a ribbon, electrical means for driving said ribbon at a plurality of spaced points thereon, and electrical contact means positioned some on the ribbon and some iixed in opposingposition thereto between the points of drive for controlling the energization of said drive.

2. A vibrator of the type described comprising a ribbon, electrical energizing means for driving said ribbon in symmetrical duplex fashion with a quasi node on the ribbon between the points of drive and means making electrical contact for controlling said energizing means positioned at said node.

3. A vibrator of the type described comprising a ribbon, means stretching said ribbon between its ends, contact means positioned substantially midway between the ends thereof, and energizing means periodically operated by said contact means positioned to act on said ribbon between the ends thereof and the position of said contact means.

4. A vibrator of the type described comprising 'a base member having clamping means at either end thereof, a ribbon element having magnetizable armatures suspended between said clamping ends over said base, electromagnetic means poing a circuit to said electromagnetic means, landmeans supported on said base for adjusting the tension on said ribbon.

5. A vibrator of the type described comprising a ribbon element having magnetizable means, means suspending said ribbon element tautly between its ends, electromagnetic means supported by said suspending means, and operatively positioned with regard to said maanetizable means, contact means operatively associated with said ribbon element for opening and closing an electric circuit to said electromagnetic means, and means mounting part of said contact means in a. fixed position relative to said ribbon element.

6. A vibrator of the type described comprising an elongated base member having clamping l5 across said contact means at the instant of openmeans at either end thereof. a ribbon element suspended between said clamping endsfof said inl.

HUGO BENIOF'F. 

